A coil material feeding unit adapted to feed to a press line the strip uncoiled from a coil material is provided with uncoilers for continuously uncoil the coil material which has been transferred to the uncoilers. The strip uncoiled from the coil material by the uncoilers is caused through a leveller to straighten the curved contour of the strip as seen immediately after the uncoiling therefrom and thereafter it is fed to the press line where it receives forming operation.
A coil material to be loaded on the uncoilers has a width different from production lot to production lot and this fact requires an operator to input into a control section of the coil material feeding unit the width of a coil material to be loaded on the uncoilers before the coil material is loaded on the uncoilers. The control section is adapted to perform control operations in correspondence to a width of the coil material on the basis of data which have been inputted thereinto.
In fact, a conventional coil material feeding unit does not measure the width of a coil material conveyed to uncoilers and moreover it does not check whether or not it coincides with the coil width data which have been inputted into the control section. This leads to such a malfunction that the inputted coil width data do not often coincide with the actual width of a coil material which has been transferred to the uncoilers, resulting in correct control operations failing to be performed.
The present invention has been made with the foregoing background in mind and its object resides in providing a coil width detecting apparatus usable for a coil material feeding unit which assures that the width of a coil material can be measured exactly and an occurrence of incorrect setting of a coil material can be prevented reliably.